Add isAnalyzingPullRequest()

src/actions-util.ts

@@ -3,6 +3,7 @@ import * as path from "path";
 
 import * as core from "@actions/core";
 import * as toolrunner from "@actions/exec/lib/toolrunner";
+import * as github from "@actions/github";
 import * as io from "@actions/io";
 import { JSONSchemaForNPMPackageJsonFiles } from "@schemastore/package";
 
@@ -363,3 +364,48 @@ export const restoreInputs = function () {
     }
   }
 };
+
+export interface PullRequestBranches {
+  base: string;
+  head: string;
+}
+
+/**
+ * Returns the base and head branches of the pull request being analyzed.
+ *
+ * @returns the base and head branches of the pull request, or undefined if
+ * we are not analyzing a pull request.
+ */
+export function getPullRequestBranches(): PullRequestBranches | undefined {
+  const pullRequest = github.context.payload.pull_request;
+  if (pullRequest) {
+    return {
+      base: pullRequest.base.ref,
+      // We use the head label instead of the head ref here, because the head
+      // ref lacks owner information and by itself does not uniquely identify
+      // the head branch (which may be in a forked repository).
+      head: pullRequest.head.label,
+    };
+  }
+
+  // PR analysis under Default Setup does not have the pull_request context,
+  // but it should set CODE_SCANNING_REF and CODE_SCANNING_BASE_BRANCH.
+  const codeScanningRef = process.env.CODE_SCANNING_REF;
+  const codeScanningBaseBranch = process.env.CODE_SCANNING_BASE_BRANCH;
+  if (codeScanningRef && codeScanningBaseBranch) {
+    return {
+      base: codeScanningBaseBranch,
+      // PR analysis under Default Setup analyzes the PR head commit instead of
+      // the merge commit, so we can use the provided ref directly.
+      head: codeScanningRef,
+    };
+  }
+  return undefined;
+}
+
+/**
+ * Returns whether we are analyzing a pull request.
+ */
+export function isAnalyzingPullRequest(): boolean {
+  return getPullRequestBranches() !== undefined;
+}

src/analyze.ts

@@ -6,7 +6,11 @@ import * as io from "@actions/io";
 import del from "del";
 import * as yaml from "js-yaml";
 
-import * as actionsUtil from "./actions-util";
+import {
+  getRequiredInput,
+  getTemporaryDirectory,
+  PullRequestBranches,
+} from "./actions-util";
 import { getApiClient } from "./api-client";
 import { setupCppAutobuild } from "./autobuild";
 import { CodeQL, getCodeQL } from "./codeql";
@@ -15,7 +19,6 @@ import { getJavaTempDependencyDir } from "./dependency-caching";
 import { addDiagnostic, makeDiagnostic } from "./diagnostics";
 import {
   DiffThunkRange,
-  PullRequestBranches,
   writeDiffRangesJsonFile,
 } from "./diff-informed-analysis-utils";
 import { EnvVar } from "./environment";
@@ -392,7 +395,7 @@ function getDiffRanges(
   // uses forward slashes as the path separator, so on Windows we need to
   // replace any backslashes with forward slashes.
   const filename = path
-    .join(actionsUtil.getRequiredInput("checkout_path"), fileDiff.filename)
+    .join(getRequiredInput("checkout_path"), fileDiff.filename)
     .replaceAll(path.sep, "/");
 
   if (fileDiff.patch === undefined) {
@@ -498,10 +501,7 @@ function writeDiffRangeDataExtensionPack(
     ranges = [{ path: "", startLine: 0, endLine: 0 }];
   }
 
-  const diffRangeDir = path.join(
-    actionsUtil.getTemporaryDirectory(),
-    "pr-diff-range",
-  );
+  const diffRangeDir = path.join(getTemporaryDirectory(), "pr-diff-range");
 
   // We expect the Actions temporary directory to already exist, so are mainly
   // using `recursive: true` to avoid errors if the directory already exists,

src/diff-informed-analysis-utils.ts

@@ -1,45 +1,12 @@
 import * as fs from "fs";
 import * as path from "path";
 
-import * as github from "@actions/github";
-
 import * as actionsUtil from "./actions-util";
+import type { PullRequestBranches } from "./actions-util";
 import type { CodeQL } from "./codeql";
 import { Feature, FeatureEnablement } from "./feature-flags";
 import { Logger } from "./logging";
 
-export interface PullRequestBranches {
-  base: string;
-  head: string;
-}
-
-function getPullRequestBranches(): PullRequestBranches | undefined {
-  const pullRequest = github.context.payload.pull_request;
-  if (pullRequest) {
-    return {
-      base: pullRequest.base.ref,
-      // We use the head label instead of the head ref here, because the head
-      // ref lacks owner information and by itself does not uniquely identify
-      // the head branch (which may be in a forked repository).
-      head: pullRequest.head.label,
-    };
-  }
-
-  // PR analysis under Default Setup does not have the pull_request context,
-  // but it should set CODE_SCANNING_REF and CODE_SCANNING_BASE_BRANCH.
-  const codeScanningRef = process.env.CODE_SCANNING_REF;
-  const codeScanningBaseBranch = process.env.CODE_SCANNING_BASE_BRANCH;
-  if (codeScanningRef && codeScanningBaseBranch) {
-    return {
-      base: codeScanningBaseBranch,
-      // PR analysis under Default Setup analyzes the PR head commit instead of
-      // the merge commit, so we can use the provided ref directly.
-      head: codeScanningRef,
-    };
-  }
-  return undefined;
-}
-
 /**
  * Check if the action should perform diff-informed analysis.
  */
@@ -70,7 +37,7 @@ export async function getDiffInformedAnalysisBranches(
     return undefined;
   }
 
-  const branches = getPullRequestBranches();
+  const branches = actionsUtil.getPullRequestBranches();
   if (!branches) {
     logger.info(
       "Not performing diff-informed analysis " +